BACKGROUND OF THE INVENTION
[0001] This invention relates to a method for the preparation of polycarbonate. More particularly
the method relates to a method of preparing polycarbonate by the melt reaction of
at least one dihydroxy aromatic compound with at least one diaryl carbonate, said
melt reaction being mediated by a transesterification catalyst, said transesterification
catalyst comprising at least one mixed alkali metal salt of phosphoric acid and a
co-catalyst.
[0002] Conventionally, polycarbonate is prepared by the reaction of a dihydroxy aromatic
compound such as bisphenol A with phosgene in the presence of an aqueous phase comprising
an acid acceptor such as sodium hydroxide and an organic solvent such as dichloromethane.
Typically, a phase transfer catalyst, such as a quaternary ammonium compound or a
low molecular weight tertiary amine, such as triethylamine is added to the aqueous
phase to enhance the polymerization rate. This synthetic method is commonly known
as the "interfacial" method for preparing polycarbonate.
[0003] The interfacial method for making polycarbonate has several inherent disadvantages.
First it is a disadvantage to operate a process which requires phosgene as a reactant
due to obvious safety concerns. Second it is a disadvantage to operate a process which
requires using large amounts of an organic solvent because elaborate precautions must
be taken to prevent adventitious release of the volatile solvent into the environment.
Third, the interfacial method requires a relatively large amount of equipment and
capital investment. Fourth, the polycarbonate produced by the interfacial process
is prone to having inconsistent color, higher levels of particulates, and higher chlorine
content, which can cause corrosion.
[0004] More recently polycarbonate has been prepared on a commercial scale in a solventless
process involving the transesterification reaction between a dihydroxy aromatic compound
(e.g. bisphenol A) and a diaryl carbonate (e.g., diphenyl carbonate) in the presence
of a transesterification catalyst. This reaction is performed in a molten state in
the absence of solvent, and is driven to completion by mixing the reactants under
reduced pressure and high temperature with simultaneous distillation of the phenol
by-product produced by the reaction. This method of preparing polycarbonate is referred
to as the "melt" process. In some respects the melt process is superior to the interfacial
method because it does not employ phosgene, it does not require a solvent, and it
uses less equipment. Moreover, the polycarbonate produced by the melt process does
not contain chlorine contamination from the reactants, has lower particulate levels,
and has a more consistent color. Therefore it is highly desirable to use the melt
process when making polycarbonate in commercial manufacturing processes.
[0005] A wide variety of transesterification catalysts have been evaluated for use in the
preparation of polycarbonate using the melt process. Alkali metal hydroxides, in particular
sodium hydroxide, have proven to be particularly effective as transesterification
catalysts. However, while alkali metal hydroxides are useful polymerization catalysts,
they are also known to promote Fries reaction along the growing polycarbonate chains
which results in the production of branched polycarbonate products. The presence of
branching sites within a polycarbonate chain can causes changes in the melt flow behavior
of the polycarbonate, which can lead to difficulties in processing.
[0006] It would be desirable, therefore, to develop a catalyst system which effects melt
polymerization while minimizing undesirable reaction products, such as branched side
reaction products.
BRIEF SUMMARY OF THE INVENTION
[0007] In one aspect, the present invention provides a method of preparing polycarbonate,
said method comprising reacting under melt polymerization conditions in the presence
of a transesterification catalyst at least one dihydroxy aromatic compound and at
least one diaryl carbonate, said transesterification catalyst comprising at least
one mixed alkali metal salt of phosphoric acid and at least one co-catalyst, said
co-catalyst comprising a quaternary ammonium salt, a quaternary phosphonium salt or
a mixture thereof.
[0008] In another aspect, the present invention relates to polycarbonates prepared by the
method of the present invention, said polycarbonates having lower levels of Fries
product than polycarbonates prepared by conventional melt polymerization methods.
DETAILED DESCRIPTION OF THE INVENTION
[0009] The present invention may be understood more readily by reference to the following
detailed description of preferred embodiments of the invention and the examples included
herein. In this specification and in the claims which follow, reference will be made
to a number of terms which shall be defined to have the following meanings.
[0010] The singular forms "a", "an" and "the" include plural referents unless the context
clearly dictates otherwise.
[0011] "Optional" or "optionally" means that the subsequently described event or circumstance
may or may not occur, and that the description includes instances where the event
occurs and instances where it does not.
[0012] As used herein the term "polycarbonate" refers to polycarbonates incorporating structural
units derived from one or more dihydroxy aromatic compounds and includes copolycarbonates
and polyester carbonates.
[0013] As used herein, the term "melt polycarbonate" refers to a polycarbonate made by the
transesterification of at least one diaryl carbonate with at least one dihydroxy aromatic
compound.
[0014] "BPA" is herein defined as bisphenol A and is also known as 2,2-bis(4-hydroxyphenyl)propane,
4,4'-isopropylidenediphenol and p,p-BPA.
[0015] As used herein, the term "bisphenol A polycarbonate" refers to a polycarbonate in
which essentially all of the repeat units comprise a bisphenol A residue.
[0016] As used herein, the term "polycarbonate" includes both high molecular weight polycarbonate
and oligomeric polycarbonate. High molecular weight polycarbonate is defined herein
as having number average molecular weight, M
n, greater than 8000 daltons, and an oligomeric polycarbonate are defined as having
number average molecular weight, M
n, less than 8000 daltons.
[0017] As used herein the term "percent endcap" refers to the percentage of polycarbonate
chain ends which are not hydroxyl groups. In the case of bisphenol A polycarbonate
prepared from diphenyl carbonate and bisphenol A, a "percent endcap" value of about
75% means that about seventy-five percent of all of the polycarbonate chain ends comprise
phenoxy groups while about 25% of said chain ends comprise hydroxyl groups. The terms
"percent endcap" and "percent endcapping" are used interchangeably.
[0018] As used herein the term "aromatic radical" refers to a radical having a valence of
at least one and comprising at least one aromatic ring. Examples of aromatic radicals
include phenyl, pyridyl, furanyl, thienyl, naphthyl, phenylene, and biphenyl. The
term includes groups containing both aromatic and aliphatic components, for example
a benzyl group, a phenethyl group or a naphthylmethyl group. The term also includes
groups comprising both aromatic and cycloaliphatic groups for example 4-cyclopropylphenyl
and 1,2,3,4-tetrahydronaphthalen-1-yl.
[0019] As used herein the term "aliphatic radical" refers to a radical having a valence
of at least one and consisting of a linear or branched array of atoms which is not
cyclic. The array may include heteroatoms such as nitrogen, sulfur and oxygen or may
be composed exclusively of carbon and hydrogen. Examples of aliphatic radicals include
methyl, methylene, ethyl, ethylene, hexyl, hexamethylene and the like.
[0020] As used herein the term "cycloaliphatic radical" refers to a radical having a valance
of at least one and comprising an array of atoms which is cyclic but which is not
aromatic, and which does not further comprise an aromatic ring. The array may include
heteroatoms such as nitrogen, sulfur and oxygen or may be composed exclusively of
carbon and hydrogen. Examples of cycloaliphatic radicals include cyclopropyl, cyclopentyl
cyclohexyl, 2-cyclohexylethy-1-yl, tetrahydrofuranyl and the like.
[0021] As used herein the term "Fries product" is defined as a structural unit of the product
polycarbonate which upon hydrolysis of the product polycarbonate affords a carboxy-substituted
dihydroxy aromatic compound bearing a carboxy group adjacent to one or both of the
hydroxy groups of said carboxy-substituted dihydroxy aromatic compound. For example,
in bisphenol A polycarbonate prepared by a melt reaction method in which Fries reaction
occurs, the Fries product includes those structural features of the polycarbonate
which afford 2-carboxy bisphenol A upon complete hydrolysis of the product polycarbonate.
[0022] The terms "Fries product" and "Fries group" are used interchangeably herein.
[0023] The terms "Fries reaction" and "Fries rearrangement" are used interchangeably herein.
[0024] As used herein the term "Fries level" refers to the amount of Fries product present
in a product polycarbonate.
[0025] As mentioned, the present invention relates to a method of preparing polycarbonate,
said method comprising reacting under melt polymerization conditions in the presence
of a transesterification catalyst at least one dihydroxy aromatic compound and at
least one diaryl carbonate, said transesterification catalyst comprising at least
one mixed alkali metal salt of phosphoric acid and at least one co-catalyst, said
co-catalyst comprising a quaternary ammonium salt, a quaternary phosphonium salt or
a mixture thereof. The mixed alkali metal salt comprises at least two different alkali
metal ions selected from the group consisting of cesium ions, sodium ions, and potassium
ions. Such mixed alkali metal phosphate catalysts are conveniently prepared by addition
of a first alkali metal hydroxide to an aqueous solution of phosphoric acid followed
by the addition of a second alkali metal hydroxide to the mixture. Such additions
are conveniently carried out as titrations in which the amounts of alkali metal hydroxides
added may be monitored by a change in the pH of the phosphoric acid solution. For
example, an aqueous solution of phosphoric acid is first treated with about 0.95 equivalents
of cesium hydroxide and subsequently with 0.6 equivalents of sodium hydroxide. The
resultant aqueous solution comprises the mixed alkali metal phosphate CsNaHPO
4 which has been found to possess improved catalytic properties over other alkali metal
phosphates containing only a single species of alkali metal ion. Typically, the mixed
alkali metal phosphate catalyst is added to the polymerization as an aqueous solution.
Thus, the preparation and use of the mixed alkali metal phosphate catalysts of the
present invention is especially convenient.
[0026] When the mixed alkali metal phosphate catalyst comprises cesium and sodium ions it
has been found that catalytic activity is optimal when said catalyst comprises between
0.85 and 1.0 equivalents of cesium and 0.1 to 0.6 equivalents of sodium per phosphoric
acid equivalent. When the mixed alkali metal phosphate catalyst comprises potassium
and sodium ions it has been found that catalytic activity is optimal when said catalyst
comprises between 0.85 and 1.0 equivalents of potassium and 0.1 to 1 equivalents of
sodium per phosphoric acid equivalent.
[0027] In melt a polymerization reaction of one or more dihydroxy aromatic compounds and
one or more diaryl carbonates, the mixed alkali metal salt of phosphoric acid is typically
employed in an amount corresponding to between 1x10
-8 and 1 x 10
-3, preferably 1 x 10
-6 and 2.5 x 10
-4 moles of mixed alkali metal salt of phosphoric acid per mole dihydroxy aromatic compound.
[0028] The dihydroxy aromatic compounds used according to the method of the present invention
may be dihydroxy benzenes, for example hydroquinone (HQ), 2-methylhydroquinone, resorcinol,
5-methylresorcinol and the like; dihydroxy naphthalenes, for example 1,4-dihydroxynathalene,
2, 6-dihydroxynaphthalene, and the like; and bisphenols, for example bisphenol A and
4, 4'-sulfonyldiphenol. Typically, the dihydroxy aromatic compound comprises at least
one bisphenol having structure I
wherein R
1 is independently at each occurrence a halogen atom, nitro group, cyano group, C
1-C
20 alkyl group, C
4-C
20 cycloalkyl group, or C
6-C
20 aryl group; n and m are independently integers 0-4; and W is a bond, an oxygen atom,
a sulfur atom, a SO
2 group, a C
1-C
20 aliphatic radical, a C
6-C
20 aromatic radical, a C
6-C
20 cycloaliphatic radical or the group
wherein R
2 and R
3 are independently a hydrogen atom, C
1-C
20 alkyl group, C
4-C
20 cycloalkyl group, or C
4-C
20 aryl group; or R
2 and R
3 together form a C
4-C
20 cycloaliphatic ring which is optionally substituted by one or more C
1-C
20 alkyl, C
6-C
20 aryl, C
5-C
21 aralkyl, C
5-C
20 cycloalkyl groups or a combination thereof.
[0029] Bisphenols having structure I are illustrated by bisphenol A; 2,2-bis(4-hydroxy-3-methylphenyl)propane;
2,2-bis(3-chloro-4-hydroxyphenyl)propane; 2,2-bis(3-bromo-4-hydroxyphenyl)propane;
2,2-bis(4-hydroxy-3-isopropylphenyl)propane; 1,1-bis(4-hydroxyphenyl)cyclohexane;
1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane; 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane,
and the like.
[0030] Typically, the diaryl carbonate used is at least one diaryl carbonate having structure
II
wherein R
4 is independently at each occurrence a halogen atom, nitro group, cyano group, C
1-C
20 alkyl group, C
1-C
20 alkoxy carbonyl group, C
4-C
20 cycloalkyl group, or C
6-C
20 aryl group; and t and v are independently integers 0-5.
[0031] Diaryl carbonates II are illustrated by diphenyl carbonate, bis(4-methylphenyl) carbonate,
bis(4-chlorophenyl) carbonate, bis(4-fluorophenyl) carbonate, bis(2-chlorophenyl)
carbonate, bis(2,4-difluorophenyl) carbonate, bis(4-nitrophenyl) carbonate, bis(2-nitrophenyl)
carbonate, bis(methyl salicyl) carbonate, and the like.
[0032] The transesterification catalyst used according to method of the present invention
comprises at least one co-catalyst, said co-catalyst being present in an amount corresponding
to between 1 x 10
-6 and 1 x 10
-2, preferably between 1 x 10
-5 and 2.5 10
-4 moles of co-catalyst per mole of dihydroxy aromatic compound employed. Typically,
the co-catalyst is at least one quaternary ammonium salt, at least one quaternary
phosphonium salt, or a mixture thereof.
[0033] In one embodiment of the present invention the co-catalyst is a quaternary ammonium
compound having structure III
wherein R
5 -R
8 are independently a C
1-C
20 alkyl group, C
4-C
20 cycloalkyl group, or a C
4-C
20 aryl group; and X
- is an organic or inorganic anion. Typically the anion X- is selected from the group
consisting of hydroxide, halide, carboxylate, phenoxide, sulfonate, sulfate, carbonate,
and bicarbonate. Hydroxide is frequently preferred. Quaternary ammonium salts having
structure III are illustrated by tetramethylammonium hydroxide, tetrabutylammonium
hydroxide, and the like.
[0034] In an alternate embodiment of the present invention the co-catalyst is a quaternary
phosphonium compound having structure IV
wherein R
9-R
12 are independently a C
1-C
20 alkyl group, C
4-C
20 cycloalkyl group, or a C
4-C
20 aryl group; and X
- is an organic or inorganic anion. Typically the anion X
- is selected from the group consisting of hydroxide, halide, carboxylate, phenoxide,
sulfonate, sulfate, carbonate, and bicarbonate. Hydroxide is frequently preferred.
Quaternary phosphonium salts having structure IV are illustrated by tetrabutylphosphonium
hydroxide, tetraoctylphosphonium hydroxide, tetrabutylphosphonium acetate, and the
like.
[0035] In structures III and IV, the anion X is typically an anion selected from the group
consisting of hydroxide, halide, carboxylate, phenoxide, sulfonate, sulfate, carbonate,
and bicarbonate. With respect to transesterifcation catalysts comprising co-catalysts
having structures III and IV, where X is a polyvalent anion such as carbonate or sulfate
it is understood that the positive and negative charges in structures III and IV are
properly balanced. For example, in tetrabutylphosphonium carbonate where R
9 - R
12 in structure IV are each butyl groups and X
- represents a carbonate anion, it is understood that X represents ½ (CO
3 -2).
[0036] The term "melt polymerization conditions" is understood to mean those conditions
necessary to effect reaction between a diaryl carbonate and a dihydroxy aromatic compound
in the presence of a transesterification catalyst. The reaction temperature is typically
in the range of 100°C to 350°C, more preferably 180°C to 310°C. The pressure may be
at atmospheric pressure, supraatmospheric pressure, or a range of pressures from atmospheric
pressure to 15 torr in the initial stages of the reaction, and at a reduced pressure
at later stages, for example in the range of 0.2 to 15 torr. The reaction time is
generally 0.1 hours to 10 hours.
[0037] The method of the present invention may be conducted as a batch process or as a continuous
process. In either case, the melt polymerization conditions used may comprise two
or more distinct reaction stages, for example, a first reaction stage in which the
starting diaryl carbonate and dihydroxy aromatic compound are converted into an oligomeric
polycarbonate and a second reaction stage wherein the oligomeric polycarbonate formed
in the first reaction stage is converted to high molecular weight polycarbonate. Such
"staged" polymerization reaction conditions are especially suitable for use in continuous
polymerization systems wherein the starting monomers are oligomerized in a first reaction
vessel and the oligomeric polycarbonate formed therein is continuously transferred
to one or more downstream reactors in which the oligomeric polycarbonate is converted
to high molecular weight polycarbonate. Typically, in the oligomerization stage the
oligomeric polycarbonate produced has a number average molecular weight of from 1000
to 7500 daltons. In one or more subsequent polymerization stages the number average
molecular weight of the polycarbonate is increased to between 8000 and 25000 daltons.
[0038] In one embodiment, the process is conducted as a two stage process. In the first
stage of this embodiment, the co-catalyst, for example tetramethylammonium hydroxide
is introduced into the reaction system comprising the dihydroxy aromatic compound
and the diaryl carbonate. The first stage is conducted at a temperature of 270 °C
or lower, preferably between 150°C and 250°C, more preferably between 150°C and 230°C.
The duration of the first stage is preferably from 2 minutes to 5 hours, even more
preferably 2 minutes to 3 hours at a pressure from atmospheric pressure to 100 torr.
It is generally preferable that oxygen be excluded from the reaction mixture during
the oligomerization and subsequent polymerization stages. Oxygen exclusion is conveniently
achieved using known techniques, for example, maintaining a positive pressure of nitrogen
in the system before and after evacuation.
[0039] The mixed alkali metal salt of phosphoric acid may be added in the first stage along
with the co-catalyst. Alternatively the mixed alkali metal salt of phosphoric acid
is introduced into the product from the first stage and further polycondensation is
conducted. The salt of the mixed alkali metal salt of phosphoric acid may be added
in its entire amount in the second stage, or it may be added in batches in the second
and subsequent stages so that the total amount is within the aforementioned ranges.
[0040] It is preferable in the second and any subsequent stages of the polycondensation
step for the reaction temperature to be raised while the reaction system is reduced
in pressure compared to the first stage. Typically, in the late stages of the polymerization
reaction the reaction mixture is heated at temperatures in a range between 240°C and
320°C under reduced pressure of 5 mm Hg or less, and preferably 1 mm Hg or less.
[0041] In one embodiment of the present invention at least one dihydroxy aromatic compound
and at least one diaryl carbonate are reacted in the presence of a transesterification
catalyst under melt polymerization conditions in the presence of a branching agent
to produce a product polycarbonate which is branched. Typically, the branching agent
may be a trisphenol such as 1, 1, 1-tris(4-hydroxyphenyl)ethane, THPE. Other branching
agents suitable for use according to the method of the present invention include triacids
such as trimellitic acid, 9-carboxyoctadecandioic acid, and the corresponding phenyl
esters thereof. Typically, the branching agent is used in an amount corresponding
to 0.001 to 0.03 moles of branching agent per mole of dihydroxy aromatic compound.
[0042] Additionally, the method of the present invention may carried out in the presence
of an endcapping agent. Thus, at least one endcapping agent, at least one dihydroxy
aromatic compound, at least one diaryl carbonate, and at least one transesterification
catalyst, said transesterification catalyst comprising at least one mixed alkali metal
salt of phosphoric acid and at least one co-catalyst, are reacted under melt polymerization
conditions to provide a product polycarbonate comprising terminal groups derived from
the endcapping agent. Typically, the endcapping agent is a monofunctional phenol such
as cardanol, p-cresol, p-tert-butylphenol, and p-cumylphenol. For example when p-tert-butylphenol
is used as the endcapping agent the product polycarbonate prepared according to the
method of the present invention comprises terminal p-tert-butylphenoxy groups.
[0043] In some aspects the method of the present invention is superior to earlier melt polymerization
methods based upon the speed at which the polymerization reaction occurs under the
influence of the mixed alkali metal phosphate catalyst co-catalyst combination employed.
Thus, higher molecular weight product polycarbonates are obtained in a shorter period
of time. Additionally, the product polycarbonates prepared according to the method
of the present invention typically possess lower levels of Fries product than product
polycarbonates prepared under comparable conditions of reaction time, reaction temperature,
catalyst loading and the like, using conventional catalyst systems. In general, it
is desirable to limit the amount of Fries product present in the product polycarbonate
to the greatest extent possible since high Fries levels can produce discoloration
and serve as sites for uncontrolled polymer branching which can affect the melt flow
properties of the product polycarbonate. Generally, the level of Fries rearrangement
product present in high molecular weight polycarbonate prepared according to the method
of the present invention is less than about 1000 parts per million, preferably less
than 500 parts per million.
[0044] It is understood, especially for melt reactions of the type presented in the instant
invention, that the purity of the monomers employed may strongly affect the properties
of the product polycarbonate. Thus, it is frequently desirable that the monomers employed
be free of, or contain only very limited amounts of, contaminants such as metal ions,
halide ions, acidic contaminants and other organic species. This may be especially
true in applications such as optical disks, (e.g. compact disks) where contaminants
present in the polycarbonate can affect disk performance. Typically the concentration
of metal ions, for example iron, nickel, cobalt, sodium, and postassium, present in
the monomer should be less than about 10 ppm, preferably less than about 1 ppm and
still more preferably less than about 100 parts per billion (ppb). The amount of halide
ion present in the polycarbonate, for example fluoride, chloride and bromide ions,
should be minimized in order to inhibit the absorption of water by the product polycarbonate
as well as to avoid the corrosive effects of halide ion on equipment used in the preparation
of the polycarbonate. Certain applications, for example optical disks, may require
very low levels of halide ion contaminants. Preferably, the level of halide ion present
in each monomer employed should be less than about 1 ppm. The presence of acidic impurities,
for example organic sulfonic acids which may be present in bisphenols such as BPA,
should be minimized since only minute amounts of basic catalysts are employed in the
oligomerization and subsequent polymerization steps. Even a small amount of an acidic
impurity may have a large effect on the rates of oligomerization and polymerization
since it may neutralize a substantial portion of the basic co-catalyst employed. Lastly,
the tendency of polycarbonates to degrade at high temperature, for example during
molding, with concomitant loss of molecular weight and discoloration correlates strongly
with the presence of contaminating species within the polycarbonate. In general, the
level of purity of a product polycarbonate prepared using a melt reaction method such
as the instant invention will closely mirror the level of purity of the starting monomers.
[0045] The polycarbonate made by the method of the present invention may optionally be blended
with any conventional additives, including but not limited to dyestuffs, UV stabilizers,
antioxidants, heat stabilizers, and mold release agents, in order to facilitate the
formation and use of a molded article. In particular, it is preferable to form a blend
of the polycarbonate made by the method of the present invention and additives which
serve as process aids during the molding process and which confer additional stability
upon the molded article. The blend may optionally comprise from 0.0001 to 10% by weight
of the desired additives, more preferably from 0.0001 to 1.0% by weight of the desired
additives.
[0046] Substances or additives which may be added to the polycarbonate of this invention,
include, but are not limited to, heat-resistant stabilizers, UV absorbers, mold-release
agents, antistatic agents, slip agents, antiblocking agents, lubricants, anticlouding
agents, coloring agents, natural oils, synthetic oils, waxes, organic fillers, inorganic
fillers, and mixtures thereof
[0047] Examples of the aforementioned heat-resistant stabilizers, include, but are not limited
to, phenol stabilizers, organic thioether stabilizers, organic phosphite stabilizers,
hindered amine stabilizers, epoxy stabilizers and mixtures thereof. The heat-resistant
stabilizer may be added in the form of a solid or liquid.
[0048] Examples of UV absorbers include, but are not limited to, salicylic acid UV absorbers,
benzophenone UV absorbers, benzotriazole UV absorbers, cyanoacrylate UV absorbers,
and mixtures thereof.
[0049] Examples of the mold-release agents include, but are not limited to natural and synthetic
paraffins, polyethylene waxes, fluorocarbons, and other hydrocarbon mold-release agents;
stearic acid, hydroxystearic acid, and other higher fatty acids, hydroxyfatty acids,
and other fatty acid mold-release agents; stearic acid amide, ethylenebisstearamide,
and other fatty acid amides, alkylenebisfatty acid amides, and other fatty acid amide
mold-release agents; stearyl alcohol, cetyl alcohol, and other aliphatic alcohols,
polyhydric alcohols, polyglycols, polyglycerols and other alcoholic mold release agents;
butyl stearate, pentaerythritol tetrastearate, and other lower alcohol esters of fatty
acid, polyhydric alcohol esters of fatty acid, polyglycol esters of fatty acid, and
other fatty acid ester mold release agents; silicone oil and other silicone mold release
agents, and mixtures of any of the aforementioned.
[0050] The coloring agent may be either pigments or dyes. Inorganic coloring agents and
organic coloring agents may be used separately or in combination in the invention.
EXAMPLES
[0051] The following examples are set forth to provide those of ordinary skill in the art
with a detailed description of how the methods claimed herein are carried out and
evaluated.
[0052] Unless indicated otherwise, parts are by weight, temperature is in °C.
[0053] Molecular weights are reported as number average (M
n) or weight average (M
w) molecular weight and were determined by gel permeation chromatography (GPC) relative
to a polycarbonate standard of known molecular weight.
[0054] Fries content was measured by the KOH methanolysis of resin and is reported as parts
per million (ppm). The Fries content was determined as follows. First, 0.50 grams
of the product polycarbonate was dissolved in 4.0 ml of THF (containing
p-terphenyl as internal standard). Next, 3.0 mL of 18% KOH in methanol was added to
this solution. The resulting mixture was stirred for two hours at room temperature.
Next, 1.0 mL of acetic acid was added, and the mixture was stirred for 5 minutes.
Potassium acetate by-product was allowed to crystallize over 1 hour. The solid was
filtered off and the resulting filtrate was analyzed by high performance liquid chromatography
(HPLC) using
p-terphenyl as the internal standard.
[0055] Catalyst solutions containing mixed alkali metal salts of phosphoric acid were prepared
by titrating a solution of phosphoric acid with two solutions of alkali metal hydroxide.
For example, a solution of phosphoric acid (1 x 10
-3 moles H
3PO
4 per liter) was treated with between 0.85 and 0.95 equivalents of cesium hydroxide
using a solution of CsOH in water (1x10
-1 moles CsOH per liter). To the resultant solution was then added between 0 and about
1 equivalents of sodium hydroxide or potassium hydroxide. The NaOH or KOH was added
as a solution of NaOH or KOH in water, said solution having a concentration of about
1x10
-1 moles of NaOH or KOH per liter. The pH of the catalyst solution was then recorded.
The catalyst solution comprised CsNaHPO
4 or CsKHPO
4 , mixed alkali metal salts of phosphoric acid, and was employed in melt polymerization
reactions to form polycarbonate.
[0056] Reactions were carried out in a 1 liter glass batch reactor equipped with a solid
nickel helical agitator. The interior surface of the glass reactor was passivated
by immersing the reactor in a dilute hydrochloric acid over night, thoroughly rinsing
the reactor with deionized water (18 mega-Ohm), and drying overnight at 70°C in a
drying oven. During polymerization reactions the reactor was heated by means of a
fluidized sand bath with a PID controller. The temperature of the reactor was measured
on the outside of the reactor near the interface between the reactor wall and sand
bath. The reactor was equipped with a distillation head and receiving vessel. The
pressure inside of the reactor was controlled by a nitrogen bleed into a vacuum pump
connected through a cold trap to the receiving vessel. Higher pressures (760mm Hg
to 40 mm Hg) were measured with a mercury barometer, and lower pressures (40 mm Hg
to 1 mm Hg) were measured with an Edward pirani gauge. The reactor was charged with
0.6570 mol BPA and 0.7096 mol diphenyl carbonate and purged with nitrogen by evacuating
the reactor and then introducing nitrogen gas. This nitrogen purge procedure was repeated
three times. After the final nitrogen exchange, the reactor was brought to about atmospheric
pressure under nitrogen and submerged into the fluidized bath which was at 180°C.
After five minutes, agitation was begun at 250 rpm. After an additional ten minutes,
the reactants were fully melted and the mixture was homogeneous. The mixed alkali
metal salt of phosphoric acid catalyst (1.00 x 10
-6 mole per mole BPA) and tetramethylammonium hydroxide co-catalyst (TMAH, 2.4 x 10
-4 mole per mole BPA) were added sequentially as aqueous solutions. The volume added
of the solution of the mixed alkali metal salt of phosphoric acid catalyst was about
600 microliters. The volume of the solution of the tetramethylammonium hydroxide co-catalyst
was about 148 microliters. When the addition of the catalyst and co-catalyst addition
was complete, timing was begun and the temperature was ramped to 240°C over a five
minute period. When a temperature of 240°C was reached, the pressure in the reactor
was reduced to 180 mm Hg. Phenol began to distill as the pressure was reduced. After
25 minutes, the pressure was again reduced to 100 mm Hg and the reaction mixture was
maintained at 240°C and 100 mm Hg for 45 minutes. The temperature was then ramped
to 260°C over a five minute period and the pressure was further reduced to 15 mm Hg.
The reaction mixture was maintained at 260°C and 15 mm Hg for 45 minutes. The temperature
was then ramped to 270°C over a five minute period and the pressure was lowered to
2 mm Hg. These conditions were maintained for 10 minutes. The temperature was then
ramped to the final "finishing temperature" over five minutes and the pressure was
reduced to 1.1 mm Hg. The finishing temperature was between about 280°C and about
310°C (See Tables). After 30 minutes, the reactor was removed from the sand bath and
the molten product polycarbonate was poured into liquid nitrogen to quench the reaction.
[0057] Unless otherwise noted, the mixed alkali metal salt of phosphoric acid catalyst was
added at 1.0 × 10
-6 moles per mole BPA, and TMAH was added at 2.5 × 10
-4 moles per mole BPA.
Comparative Examples 1-6
[0058] In Comparative Examples 1-6 the catalyst was a cesium phosphate solution prepared
by titration of a 1 x 10
-3 molar solution of phosphoric acid in water with a 0.1 molar solution of cesium hydroxide
(CsOH). The pH of the catalyst solution and the number of equivalents of cesium ion
present were varied. The polymerizations in Comparative Examples 1-6 were conducted
as described in the general experimental description. TMAH (2.5 X10
-4 mole per mole BPA) was used as a co-catalyst. The data in Table 1 illustrate the
effect of increasing cesium ion concentration on polymerization rate (as judged by
the molecular weight of the product polycarbonate) and Fries level in the product
polycarbonate.
TABLE 1 EFFECT OF CESIUM ION CONCENTRATION ON POLYMERIZATION RATE AND FRIES SELECTIVITY
(Catalyst = CsOH +H
3PO
4, Co-Catalyst = TMAH)
Example |
Equivalents "Cs" |
pH of catalyst solutiona |
Finishing Temperature |
Product Mn |
Fries Level (ppm) |
CE-1 |
0.855 |
3.20 |
310°C |
2199 |
none observed |
CE-2 |
0.900 |
3.42 |
310°C |
8774 |
377 |
CE-3 |
0.940 |
3.72 |
310°C |
10045 |
536 |
CE-4 |
0.975 |
4.40 |
310°C |
10104 |
1167 |
CE-5 |
0.990 |
5.03 |
310°C |
11222 |
1152 |
CE-6 |
01.145 |
6.30 |
310°C |
11448 |
1682 |
a No co-catalyst is present in these catalyst solutions. |
Comparative Examples 7-12
[0059] Comparative Examples 7-12 are provided to illustrate the behavior of a catalyst system
consisting of sodium hydroxide (1 x 10
-6 mole per mole BPA) together with TMAH co-catalyst (2.5 x 10
-4 mole per mole BPA) relative to Comparative Examples 1-6 and the working Examples
1-32 presented. The polymerizations were run as described in the general experimental
description using sodium hydroxide instead of the mixed alkali metal salt of phosphoric
acid salt catalyst of the present invention. Final "finishing temperatures" are listed
in Table 2.
TABLE 2 COMPARATIVE EXAMPLES ILLUSTRATING POLYMERIATION REACTIONS CATALYZED BY SODIUM
HYDROXIDE + TMAH
Example |
Equivalents NaOH a |
Finishing Temperature |
Product Mn |
Fries Level (ppm) |
CE-7 |
1.0 |
280°C |
6784 |
288 |
CE-8 |
0.4 |
280°C |
5551 |
72 |
CE-9 |
1.0 |
295°C |
8500 |
622 |
CE-10 |
0.1 |
310°C |
2403 |
None observed |
CE-11 |
0.2 |
310°C |
4241 |
---* |
CE-12 |
1.0 |
310°C |
9155 |
1195 |
a 1.0 equivalent of NaOH is 1 x 10-6 moles of NaOH per mole of BPA.* Fries level not determined |
[0060] As can be seen by comparing the data in Tables 1 and 2, the use of more than 0.94
equivalents of cesium (CE-3, catalyst solution pH = 3.72) provides no advantage in
terms of Fries selectivity over sodium hydroxide. The use of a catalyst solution prepared
from aqueous phosphoric acid and 0.94 equivalents of cesium hydroxide or less (Comparative
Examples 1-3), lowers the amount of Fries product produced but also lowers the overall
polymerization rate which results in a lower molecular weight product polycarbonate.
High molecular weight polycarbonate can be achieved using a catalyst solution prepared
from an aqueous solution of phosphoric acid and more than 0.94 equivalents of cesium
hydroxide (Comparative Examples 4-6) but as the molecular weight of the product polycarbonate
is increases so too does the level of Fries product.
Examples 1-32
[0061] Data for melt polymerizations using mixed sodium-cesium salts of phosphoric acid
are given in Table 3 below. The data given for Examples 1-15 together with the Comparative
Examples illustrate the synergistic effect of sodium ion in catalyst systems prepared
from cesium hydroxide and phosphoric acid, "cesium phosphate" catalysts.
TABLE 3 SYNERGISTIC EFFECT OF SODIUM HYDROXIDE ON "CESIUM PHOSPHATE" CATALYST (TMAH
PRESENT IN ALL CASES)
Example |
Equiv. "Cs" |
pH of catalyst soln.a |
Equiv. NaOH added |
PH of catalyst soln. + NaOH |
Finishing Temperature |
Product Mn |
Fries Level (ppm) |
CE-13 |
0.900 |
3.42 |
--- |
--- |
280°C |
1638 |
n.d. c |
1 |
0.900 |
3.42 |
0.2 |
5.79 |
280°C |
6066 |
42 |
2 |
0.900 |
3.42 |
0.4 |
6.13 |
280°C |
6493 |
50 |
3 |
0.900 |
3.42 |
0.6 |
6.63 |
280°C |
7088 |
88 |
CE-7 |
0 |
--- |
1.0 b |
--- |
280°C |
6784 |
288 |
CE-14 |
0.900 |
3.42 |
0 |
--- |
295°C |
5854 |
31 |
4 |
0.900 |
3.42 |
0.2 |
5.79 |
295°C |
8145 |
238 |
5 |
0.900 |
3.42 |
0.4 |
6.13 |
295°C |
8246 |
315 |
6 |
0.900 |
3.42 |
0.6 |
6.63 |
295°C |
8773 |
250 |
CE-9 |
0 |
--- |
1.0 b |
--- |
295°C |
8500 |
622 |
CE-2 |
0.900 |
3.42 |
0 |
--- |
310°C |
8774 |
377 |
7 |
0.900 |
3.42 |
0.2 |
5.79 |
310°C |
9369 |
467 |
8 |
0.900 |
3.42 |
0.4 |
6.13 |
310°C |
8992 |
608 |
9 |
0.900 |
3.42 |
0.6 |
6.63 |
310°C |
9808 |
796 |
CE-12 |
0 |
--- |
1.0 b |
--- |
310°C |
9155 |
1195 |
CE-15 |
0.940 |
3.72 |
0 |
--- |
280°C |
3478 |
<20 |
10 |
0.940 |
3.72 |
0.1 |
5.42 |
280°C |
4466 |
<20 |
11 |
0.940 |
3.72 |
0.2 |
6.00 |
280°C |
5806 |
<20 |
12 |
0.940 |
3.72 |
0.3 |
6.30 |
280°C |
6802 |
42 |
CE-16 |
0.940 |
3.72 |
0 |
--- |
295°C |
6957 |
45 |
13 |
0.940 |
3.72 |
0.1 |
5.42 |
295°C |
8307 |
222 |
14 |
0.940 |
3.72 |
02 |
6.00 |
295°C |
8759 |
380 |
CE-3 |
0.940 |
3.72 |
0 |
--- |
310°C |
10045 |
536 |
15 |
0.940 |
3.72 |
0.1 |
|
310°C |
10171 |
444 |
a No TMAH is present in these catalyst solutions b 1.0 equivalent of NaOH is 1 x 10-6 moles of NaOH per mole of BPA c "n.d." = none detected |
[0062] Data for melt polymerizations using mixed sodium-potassium salts of phosphoric acid
are given in Table 4 below. The data given for Examples 1.6-32 together with the Comparative
Examples illustrate the synergistic effect of sodium ion in catalyst systems prepared
from potassium hydroxide and phosphoric acid, "potassium phosphate" catalysts.
TABLE 4 SYNERGISTIC EFFECT OF SODIUM HYDROXIDE ON "POTASSIUM PHOSPHATE" CATALYST (TMAH
PRESENT IN ALL CASES)
Example |
Equiv. "K" |
pH of catalyst soln.a |
Equiv. NaOH added b |
pH of catalyst soln. + NaOH |
Finishing Temperature |
Product Mn |
Fries Level (ppm)c |
16 |
|
3.7 |
0.6 |
|
295°C |
7490 |
102 |
17 |
|
3.7 |
0.6 |
|
310°C |
9556 |
407 |
CE-17 |
1.0 |
4.8 |
0 |
--- |
280°C |
1550 |
n.d.c |
18 |
1.0 |
4.8 |
0.4 |
6.5 |
280°C |
4459 |
41 |
19 |
1.0 |
4.8 |
0.6 |
6.83 |
280°C |
5542 |
25 |
20 |
1.0 |
4.8 |
0.8 |
7.38 |
280°C |
6430 |
62 |
21 |
1.0 |
4.8 |
1.0b |
|
280°C |
6870 |
80 |
22 |
1.0 |
4.8 |
0.6 |
6.83 |
295°C |
6909 |
97 |
23 |
1.0 |
4.8 |
0.8 |
7.38 |
295°C |
7893 |
141 |
24 |
1.0 |
4.8 |
1.0b |
|
295°C |
8168 |
203 |
CE-18 |
1.0 |
4.8 8 |
0 |
--- |
310°C |
6279 |
109 |
24 |
1.0 |
4.8 |
0.6 |
6.83 |
310°C |
8874 |
242 |
25 |
1.0 |
4.8 |
0.8 |
7.38 |
310°C |
9070 |
364 |
CE-19 |
|
5.2 |
0 |
--- |
280°C |
1699 |
n.d.c |
26 |
|
5.2 |
0.6 |
|
280°C |
7039 |
56 |
27 |
|
5.2 |
0.6 |
|
295°C |
8173 |
215 |
28 |
|
5.2 |
0.6 |
|
310°C |
9473 |
414 |
29 |
|
6.0 |
0.4 |
|
280°C |
6189 |
69 |
CE-20 |
|
6.5 |
0 |
--- |
280°C |
2216 |
n.d.c |
30 |
|
6.5 |
0.4 |
|
280°C |
6507 |
93 |
31 |
|
6.5 |
0.4 |
|
295°C |
8047 |
292 |
32 |
|
6.5 |
0.4 |
|
310°C |
9762 |
457 |
CE-7 |
0 |
--- |
1.0 |
--- |
280°C |
6784 |
288 |
CE-9 |
0 |
--- |
1.0 |
--- |
295°C |
8500 |
622 |
CE-12 |
0 |
--- |
1.0 |
--- |
310°C |
9155 |
1195 |
a No TMAH is present in these catalyst solutions b 1.0 equivalent of NaOH is 1 x 10-6 moles of NaOH per mole of BPA.c "n.d." = none detected |
[0063] The data in Tables 3 and 4 illustrate the effectiveness of the mixed alkali metal
salts of phosphoric acid as melt polymerization depends on the reaction temperature
as well alkali metal used. Comparative Example 17 illustrates the behavior of a catalyst
prepared by treating aqueous phosphoric acid with 1 equivalent of postassium hydroxide
(KH
2PO
4). Thus at the stoichiometric equivalence point for the KH
2PO
4 (pH = 4.8) salt formation, the catalyst is ineffective as a melt polymerization catalysts
even in the presence of the co-catalyst (TMAH). Similarly, NaH
2PO
4 is ineffective as a melt polymerization catalyst, the presence of a tetramethylammonium
hydroxide (TMAH) or terabutylphosphonium hydroxide co-catalyst notwithstanding, even
when final finishing temperatures as high as 310°C are used. Of the simple mono alkali
metal phosphates, NaH
2PO
4, KH
2PO
4, and CsH
2PO
4, only the mono cesium salt was effective as a polymerization catalyst relative to
sodium hydroxide (See Comparative Examples 3-6, Table 1 relative to Comparative Example
12 of Table 2). In range finding experiments it was found that although the disodium
salt of phosphoric acid was ineffective as a polymerization catalyst under the melt
reaction condition described here, the dipotassium salt (K
2PO
4) provided excellent polymerization rates. As is illustrated in the Examples of Tables
3 and 4 high reaction rates and low Fries levels can be achieved when, in addition
to properly adjusting the of the ratio of cesium hydroxide or potassium hydroxide
to phosphoric acid, between about 0.1 equivalents and about 1.0 equivalents of sodium
hydroxide is added to the catalyst solution. Equivalents of sodium hydroxide are referenced
to phosphoric acid. One equivalent of sodium hydroxide corresponds to 1 mole of sodium
hydroxide per 1 mole of phosphoric acid. In the experiments presented here, the ratio
of cesium hydroxide or potassium hydroxide to phosphoric acid is reflected by the
initial pH of the mixture prepared from aqueous phosphoric acid and cesium hydroxide
or potassium hydroxide (See Column headed "pH of catalyst soln." In Tables 3 and 4).
The use of cesium salts is optimal when less than one equivalent of cesium hydroxide
is used to prepare the initial catalyst solution (cesium phosphate solution). The
addition of between 0.1 and about 0.6 equivalents of NaOH to the initial catalyst
solution provides the mixed alkali metal phosphate catalyst comprising both sodium
and cesium ions. The use of the mixed alkali metal phosphate catalyst affords high
molecular weight product polycarbonate containing reduced levels of Fries product
(e.g. Compare Example 15 with Comparative Examples 3 and 12, Table 3) and permits
the maximization polymerization rate while keeping Fries product formation to a minimum.
[0064] The potassium salts (Table 4) appear to be inherently less active catalysts than
the cesium salts featured in Table 3 and a useful synergistic effect is noted when
a slightly larger amount of sodium hydroxide is added used to produce a mixed alkali
metal phosphate catalyst which is somewhat richer in sodium ion than the corresponding
catalysts in Table 3 having about the same activity. Finally, it should be noted that
the product polycarbonate molecular weight as well as the level of Fries product it
contains reflects the "finishing temperature" employed (i.e. final polymerization
temperature) in the polymerization reaction.
Transesterification Kinetics Model Systems
[0065] A series of kinetics measurements were made in model reaction systems in order to
probe the inherent catalytic activity of the mixed alkali metal phosphate catalysts.
No co-catalyst was employed in these model reactions. Rate constants and activation
energies for several of the catalyst systems used in the present invention were evaluated.
All glassware employed in the kinetic study was washed with dilute aqueous HC1, rinsed
with deionized water and then soaked in deionized water for 12 hr followed by drying.
Para-
tert-octylphenol ("OP") was recrystallized from hot hexanes (1 g : 10 mL) at least three
times. Bis(p-cumylphenyl) carbonate ("PCPC") was recrystallized from a minimum amount
of boiling ethanol. The purity of the octylphenol was checked by heating a 2:1 molar
mixture of "OP" and "PCPC" to 240 °C for 5 minutes, 220°C for 10 minutes or 200 °C
for 15 minutes and then analyzing the reaction mixture by HPLC. The octylphenol was
considered to be of sufficient purity if conversion of the starting materials to the
transesterification cross products (p-cumylphenyl 4-tert-octylphenyl) carbonate and
bis(4-tert-octylphenyl) carbonate was less then 1%.
[0066] Catalyst samples were prepared in liquefied phenol, a 9:1 phenol : H2O mixture by
volume. Kinetics measurements with CsH
2P0
4 + 0.6 equivalents NaOH (240 °C) were carried out as follows. Samples of p-
tert-octylphenol (1.86 grams, 9.0 millimole) and bis(p-cumylphenyl) carbonate (PCPC) were
loaded into a single-neck round bottom flask. The reaction vessel was then purged
with nitrogen and submersed in a pre-equilibrated silicon oil bath at 240 °C for 5
minutes. A "time zero" aliquot was then taken by pipette followed by the addition
of the catalyst solution (45 microliters of a 2 millimolar solution, 20 ppm with respect
to PCPC) by syringe. Samples were taken periodically over a 40 minute reaction period
and analyzed by HPLC. The data reveal higher rate constants for the mixed alkali metal
phosphate catalysts of the present invention relative to catalysts comprising cesium
phosphate alone.
TABLE 5 MODEL REACTION KINETICS FOR MIXED ALKALI METAL PHOSPHATE CATALYSTS COMPRISING
CESIUM AND SODIUM
Catalyst |
Temp. (°C) |
Catalyst Loading (ppm) |
Rate Constanta k1 |
Ea (kcal/mol) |
A ([L/mol]2/min) |
Predicted a k300 |
Ab |
240 |
20 |
2918 |
25.58 |
2.27x1014 |
40168 |
A |
220 |
20 |
1049 |
A |
200 |
20 |
350 |
Bc |
240 |
20 |
1095 |
18.37 |
1.01 x 1011 |
10044 |
B |
220 |
20 |
649 |
B |
200 |
20 |
352 |
Cd |
240 |
20 |
1210 |
21.52 |
1.76 x 1012 |
10928 |
C |
220 |
20 |
499 |
C |
200 |
20 |
203 |
De |
240 |
20 |
349 |
12.30 |
6.1x107 |
1248 |
D |
220 |
20 |
220 |
D |
200 |
20 |
126 |
a Rate constant per ppm unit catalyst (L2[mol2.min]). b Catalyst A = CsH2PO4 + 0.6 equiv. NaOH c Catalyst B = CsH2PO4 + 0.4 equiv. NaOH d Catalyst C = CsH2PO4 + 0.2 equiv. NaOH e Catalyst D = CsH2PO4 without added sodium hydroxide |
[0067] Table 6 below provides analogous kinetic data for mixed alkali metal phosphate catalysts
comprising potassium and sodium. As in Table 5, the data demonstrate the greater inherent
catalytic activity of the mixed alkali metal phosphates relative to the salts of phosphoric
acid containing a single alkali metal ion.
TABLE 6 MODEL REACTION KINETICS FOR MIXED ALKALI METAL PHOSPHATE CATALYSTS COMPRISING
POTASSIUM AND SODIUM
Catalyst |
Temp. (°C) |
Catalyst Loading (ppm) |
Rate Constanta k1 |
Ea (kcal/mol) |
A ([L/mol]2/min) |
Predicted a k300 |
Eb |
240 |
56 |
5973 |
1946 |
1.12x1012 |
42634 |
E |
220 |
56 |
2606 |
E |
200 |
56 |
1118 |
Fc |
240 |
56 |
40 |
|
|
|
a Rate constant per ppm unit catalyst (L2/[mol2.min]). b Catalyst E = KH2PO4 +0.8 equivalents NaOH c Catalyst F = KH2PO4 without added sodium hydroxide |
1. Verfahren zur Herstellung von Polycarbonat, bei welchem Verfahren man unter Schmelzpolymerisationsbedingungen
in Gegenwart eines Umesterungskatalysators wenigstens eine aromatische Dihydroxyverbindung
und wenigstens ein Diarylcarbonat miteinander umsetzt, wobei der Umesterungskatalysator
wenigstens ein gemischtes Alkalimetallsalz von Phosphorsäure und wenigstens einen
Co-Katalysator aufweist, wobei der Co-Katalysator ein quaternäres Ammoniumsalz, ein
quaternäres Phosphoniumsalz oder eine Mischung davon umfasst.
2. Verfahren nach Anspruch 1, wobei das gemischte Alkalimetallsalz wenigstens zwei Alkalimetallionen
umfasst ausgewählt aus der Gruppe bestehend aus Cäsium-, Natrium- und Kaliumalkalimetallionen.
3. Verfahren nach Anspruch 2, wobei das Salz zwischen 0,85 und 1,0 Äquivalenten Cäsium
umfasst und 0,1 bis 0,6 Äquivalenten Natrium pro Phosphorsäureäquivalent.
4. Verfahren nach Anspruch 1, wobei das gemischte Alkalimetallsalz Kalium- und Natriumionen
umfasst.
5. Verfahren nach Anspruch 4, wobei das Salz zwischen 0,85 und 1,0 Äquivalenten Kalium
und 0,1 bis 0,6 Äquivalenten Natrium pro Phosphorsäureäquivalent aufweist.
6. Verfahren nach Anspruch 1, wobei die aromatische Dihydroxyverbindung ein Bisphenol
ist mit der Struktur I
worin R
1 unabhängig bei jedem Auftreten ein Halogenatom, Nitrogruppe, Cyanogruppe, C
1-C
20 Alkylgruppe, C
4-C
20 Cycloalkylgruppe, oder C
6-C
20 Arylgruppe ist; n und m unabhängig ganze Zahlen von 0 bis 4 sind; und W eine Bindung
ist, ein Sauerstoffatom, ein Schwefelatom, eine SO
2 Gruppe, ein C
1-C
20 aliphatischer Rest, C
6-C
20 aromatischer Rest, C
6-C
20 cycloaliphatischer Rest oder die Gruppe
worin R
2 und R
3 unabhängig ein Wasserstoffatom sind, C
1-C
20 Alkylgruppe, C
4-C
20 Cycloalkylgruppe, oder C
4-C
20 Arylgruppe; R
2 und R
3 zusammen einen C
4-C
20 cycloaliphatischen Ring bilden, der optional mit ein oder mehreren C
1-C
20 Alkyl-, C
6-C
20 Aryl-, C
5-C
21 Aralkyl-, C
5-C
20 Cycloalkylgruppen oder Kombinationen davon substituiert ist.
7. Verfahren nach Anspruch 1, worin das Diarylcarbonat die Struktur II hat
worin R
4 unabhängig bei jedem Auftreten ein Halogenatom, Nitrogruppe, Cyanogruppe, C
1-C
20 Alkylgruppe, C
1-C
20 Alkoxycarbonylgruppe, C
4-C
20 Cycloalkylgruppe oder C
6-C
20 Arylgruppe ist; und t und v unabhängig ganze Zahlen von 0 bis 5 sind.
8. Verfahren nach Anspruch 1, wobei die quaternäre Ammoniumverbindung die Struktur III
hat
worin R
5 bis R
8 unabhängig eine C
1-C
20 Alkylgruppe sind, C
4-C
20 Cycloalkylgruppe, oder eine C
4-C
20 Arylgruppe; und X
- ein organisches oder anorganisches Anion ist; und wobei die Phosphoniumverbindung
die Struktur IV hat
worin R
9 bis R
12 unabhängig eine C
1-C
20 Alkylgruppe sind, C
4-C
20 Cycloalkylgruppe, oder eine C
4-C
20 Arylgruppe; und X
- ein organisches oder anorganisches Anion ist.
9. Verfahren zur Herstellung von Polycarbonat, bei welchem Verfahren man wenigstens eine
aromatische Dihydroxyverbindung mit wenigstens einem Diarylcarbonat unter Schmelzpolymerisationsbedingungen
in Gegenwart eines Umesterungskatalysators in Berührung bringt, wobei der Umesterungskatalysator
wenigstens ein gemischtes Alkalimetallsalz von Phosphorsäure und wenigstens einen
Co-Katalysator umfasst, wobei der Co-Katalysator ein quaternäres Ammoniumsalz aufweist,
ein quaternäres Phosphoniumsalz oder eine Mischung davon, wobei man das in Berührung
bringen in wenigstens zwei Stufen ausführt.
10. Verfahren zur Herstellung von Polycarbonat, bei welchem Verfahren man Diphenylcarbonat
mit Bisphenol A in Gegenwart eines Umesterungskatalysators bei einer Temperatur im
Bereich zwischen 180 °C und 310 °C und einem Druck im Bereich von 101325 Pa (760 Torr)
und 133,32 Pa (1 Torr) in Berührung bringt um ein Produkt Bisphenol A Polycarbonat
zu erhalten, wobei der Umesterungskatalysator wenigstens ein gemsichtes Alkalimetallsalz
der Phosphorsäure aufweist und wenigstens Co-Katalysator, wobei der Co-Katalysator
ein quaternäres Ammoniumsalz, ein quaternäres Phosphoniumsalz, oder eine Mischung
aufweist.
1. Procédé de préparation de polycarbonate, ledit procédé comprenant la mise en réaction
sous des conditions de polymérisation par fusion, en la présence d'un catalyseur de
transestérification, d'au moins un composé aromatique dihydroxy et d'au moins un carbonate
diaryle, ledit catalyseur de transestérification comprenant au moins un sel d'acide
phosphorique de métal alcalin mélangé et au moins un cocatalyseur, ledit cocatalyseur
comprenant un sel d'ammonium quaternaire, un sel de phosphonium quaternaire ou un
mélange de ceux-ci.
2. Procédé selon la revendication 1, dans lequel ledit sel de métal alcalin comprend
au moins deux ions de métal alcalin sélectionnés à partir du groupe constitué par
des ions de métal alcalin de césium, de sodium et de potassium.
3. Procédé selon la revendication 2, dans lequel ledit sel comprend entre 0,85 et 1,0
équivalent de césium et 0,1 à 0,6 équivalent de sodium par équivalent d'acide phosphorique.
4. Procédé selon la revendication 1, dans lequel ledit sel de métal alcalin mélangé comprend
des ions potassium et sodium.
5. Procédé selon la revendication 4, dans lequel ledit sel comprend entre 0,85 et 1 équivalent
de potassium et 0,1 à 1,0 équivalent de sodium par équivalent d'acide phosphorique.
6. Procédé selon la revendication 1, dans lequel ledit composé aromatique dihydroxy est
un bisphénol présentant la structure (I)
dans laquelle R
1 est, de manière indépendante, à chaque occurrence un atome d'halogène, un groupe
nitro, un groupe cyano, un groupe alkyle en C
1 à C
20, un groupe cycloalkyle en C
4 à C
20 ou un groupe aryle en C
6 à C
20 ; et n et m sont, de manière indépendante, des entiers de 0 à 4 ; et w est une liaison,
un atome d'oxygène, un atome de soufre, un groupe SO
2, un radical aliphatique en C
1 à C
20, un radical aromatique en C
6 à C
20, un radical cycloaliphatique en C
6 à C
20 ou le groupe
dans lequel R
2 et R
3 sont, de manière indépendante, un atome d'hydrogène, un groupe alkyle en C
1 à C
20, un groupe cycloalkyle en C
4 à C
20 ou un groupe aryle en C
4 à C
20 ; ou R
2 et R
3 forment ensemble un cycle cycloaliphatique en C
4 à C
20 qui est, en variante, substitué par un ou plusieurs groupes alkyles en C
1 à C
20, aryles en C
6 à C
20, aralkyles en C
5 à C21, cycloalkyles en C
5 à C
20 ou une combinaison de ceux-ci.
7. Procédé selon la revendication 1, dans lequel ledit carbonate diaryle présente la
structure (II)
dans laquelle R
4 est, de manière indépendante, à chaque occurrence un atome d'halogène, un groupe
nitro, un groupe cyano, un groupe alkyle en C
1 à C
20, un groupe carbonyle alkoxy en C
1 à C
20, un groupe cycloalkyle en C
4 à C
20 ou un groupe aryle en C
6 à C
20 ; et t et v sont, de manière indépendante, des entiers de 0 à 5.
8. Procédé selon la revendication 1, dans lequel ledit composé ammonium quaternaire présente
la structure (III)
dans laquelle R
5 à R
8 sont, de manière indépendante, un groupe alkyle en C
1 à C
20, un groupe cycloalkyle en C
4 à C
20 ou un groupe aryle en C
4 à C
20; et X-est un anion organique ou inorganique ; et dans lequel ledit composé phosphonium
présente la structure (IV)
dans laquelle R
9 à R
16 sont, de manière indépendante, un groupe alkyle en C
1 à C
20, un groupe cycloalkyle en C
4 à C
20 ou un groupe aryle en C
4 à C
20 ; et X-est un anion organique ou inorganique.
9. Procédé de préparation de polycarbonate, ledit procédé comprenant la mise en contact
d'au moins un composé aromatique dihydroxy avec au moins un carbonate de diaryle sous
des conditions de polymérisation par fusion en la présence d'un catalyseur de transestérification,
ledit catalyseur de transestérification comprenant au moins un sel d'acide phosphorique
de métal alcalin mélangé et au moins un cocatalyseur, ledit cocatalyseur comprenant
un sel d'ammonium quaternaire, un sel de phosphonium quaternaire ou un mélange de
ceux-ci, ladite mise en contact étant réalisée en au moins deux étapes.
10. Procédé de fabrication de polycarbonate, ledit procédé comprenant la mise en contact
de carbonate de diphényle avec un bisphénol A en la présence d'un catalyseur de transestérification
à une température dans une plage comprise entre 180°C et 310°C et une pression dans
une plage entre 101325 Pa (760 Torr) et 133,32 Pa (1 Torr) afin d'obtenir un produit
polycarbonate de bisphénol A, ledit catalyseur de transestérification comprenant au
moins un sel d'acide phosphorique de métal alcalin mélangé et au moins un cocatalyseur,
ledit cocatalyseur comprenant un sel d'ammonium quaternaire, un sel de phosphonium
quaternaire ou un mélange de ceux-ci.